tert-butyl 4-chlorobenzyl(2-((3aS,5aR,5bR,7aR,9S,11aR,11bR,13aS)-9-hydroxy-1-isopropyl-5a,5b,8,8,11a-pentamethyl-3,3a,4,5,5a,5b,6,7,7a,8,9,10,11,11a,11b,12,13,13a-octadecahydro-2H-cyclopenta[a]chrysen-3a-yl)-2-oxoethyl)carbamate 在
甲醇 、 sodium tetrahydroborate 作用下,
以
四氢呋喃 为溶剂,
反应 2.0h,
以52%的产率得到4-((3aS,5aR,5bR,7aR,9S,11aR,11bR,13aS)-3a-((S)-2-((tert-butoxycarbonyl)(4-chlorobenzyl)amino)-1-hydroxyethyl)-1-isopropyl-5a,5b,8,8,11a-pentamethyl-3,3a,4,5,5a,5b,6,7,7a,8,9,10,11,11a,11b,12,13,13a-octadecahydro-2H-cyclopenta[a]chrysen-9-yl) 1-tert-butyl 2,2-dimethylsuccinate